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DIESEL STORAGE TANK DESIGN CALCULATION - API 650
1 .0 DESIGN CODE & SPECIFICATIONDESIGN CODE : API 650 11th Edition
1 .1 TANKItem number : 1Roof ( Open/Close ) : CloseType of roof ( Cone-roof / Dome-roof / Flat-roof / NA ) : Cone-roof
1 .2 GEOMETRIC DATAInside diameter , Di ( corroded ) (@ 14,000 mm ) = 14,006Nominal diameter, Dn ( new ) ( based on 1st shell course ) = 14,010Nominal diameter, Dc ( corroded ) ( based on 1st shell course ) = 14,013Tank height (tan/tan), H = 7,353Specific gravity of operating liquid , S.G. (Actual) = 0.850Specific gravity of operating liquid , S.G. (Design) = 0.85Nominal capacity , V = 1133Maximum design liquid level, HL = 7,353
1 .3 PRESSURE & TEMPERATUREDesign pressure : Upper , Pu (Atmospheric) = 0.00
: Lower , Pl = 0.00Design temperature : Upper , Tu = 70
: Lower , Tl = -17
1 .4 MATERIAL & MECHANICAL PROPERTIES
Component Material Tensile Yield CorrosionStress Stress Allowance
St(N/mm²) Sy(N/mm²) c.a.(mm)PLATEShell Plate ( Mat'l Code # 1 ) (bot) A 516 GR. 65N 448.00 241.00 3.000
( Mat'l Code # 2 ) (top) A 516 GR. 65N 448.00 241.00 3.000Annular Plate A 516 GR. 65N 448.00 241.00 3.000Bottom Plate A 516 GR. 65N 448.00 241.00 3.000Roof Plate A 516 GR. 65N 448.00 241.00 3.000STRUCTURE MEMBERSRoof structure (rafter,bracing,etc ) A 516 GR. 65N 448.00 241.00 3.00Top Curb Angle A 516 GR. 65N 448.00 241.00 3.00Intermediate Wind Girder A 516 GR. 65N 448.00 241.00 3.00
SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD2 .0 SHELL DESIGN 2 .1 GEOMETRIC DATA
Plate size used : 1,220Shell plate min. width as per PTS 34.51.01.31 clause 6.3 : 1,220
2 .2 MATERIAL & MECHANICAL PROPERTIES
No Material Specified Specified Yield stress Max. allow Max. allow Corrosionused min. tensile min. yield reduction fac design hydro.test allowance
stress stress ( App. M ) stress stressSt (N/mm²) Sy (Nmm²) k Sd (N/mm²) St (N/mm²) c.a (mm)
1 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.002 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.003 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.004 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.005 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.006 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.00
7 A 516 GR. 65N 448.00 241.00 1.000 160.67 180.75 3.008 - - - - - - -9 - - - - - - -10 - - - - - - -
2 .3 SPECIFIED MINIMUM SHELL THICKNESSSpecification : API 650 11th EditionMinimum thickness as per API 650 cl 5.6.1.1 = 5.00Minimum thickness as per PTS 34.51.01.31 = 9.00
2 .4 SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD ( CLAUSE 5.6.3.1 )
SI METRIC UNIT :-Design shell thickness, ( in mm )
4.9Dc ( [H+Hi] - 0.3 ).Gtd = + c.a
SdHydrostatic test shell thickness , ( in mm ) t.min = Min. of t.design, t.hydo &
4.9Dn ( H - 0.3 ) min. thickness as per PTS.tt =
St tsc = Thicknes selected & usedGravitational force = 9.81 m/s
2 .5 CALCULATION & RESULTS
No. Mat'l Material Width Height t.design t.hydro. t.min tsc.Code (mm) (mm) (mm) (mm) (mm) (mm)No.
1 1 A 516 GR. 65N 1,220 7,353 5.56 2.68 9.00 10.002 1 A 516 GR. 65N 1,220 6,133 5.12 2.22 9.00 10.003 1 A 516 GR. 65N 1,220 4,913 4.68 1.75 9.00 10.004 1 A 516 GR. 65N 1,220 3,693 4.23 1.29 9.00 10.005 1 A 516 GR. 65N 1,220 2,473 3.79 0.82 9.00 10.006 1 A 516 GR. 65N 1,220 1,253 3.34 0.36 9.00 10.007 1 A 516 GR. 65N 1,220 33 2.90 -0.10 9.00 10.008 1 - 2,020 -1,187 #VALUE! #VALUE! #VALUE!9 1 - -3,207 -3,207 #VALUE! #VALUE! #VALUE!
2 .6 MAXIMUM ALLOWABLE STRESS
No. Height t.min tsc. H' H' max P'max(mm) (mm) (mm) (mm) (mm) (mm)
1 7,353 9.00 10.00 7,353 19,574.62 12221.62 119,894.112 6,133 9.00 10.00 6,133 19,574.62 13441.62 131,862.313 4,913 9.00 10.00 4,913 19,574.62 14661.62 143,830.514 3,693 9.00 10.00 3,693 19,574.62 15881.62 155,798.715 2,473 9.00 10.00 2,473 19,574.62 17101.62 167,766.916 1,253 9.00 10.00 1,253 19,574.62 18321.62 179,735.117 33 9.00 10.00 33 19,574.62 19541.62 191,703.318 -1,187 #VALUE! 0.00 -1,187 #VALUE! #VALUE! #VALUE!9 -3,207 #VALUE! 0.00 -3,207 #VALUE! #VALUE! #VALUE!
H' = Effective liquid head at design pressureH' max = Max. liquid head for tsc.P'max = Max. allowable stress for tsc.Pmax = Max. allowable stress at shell course.
∆ HN/m²
BOTTOM & ANNULAR PLATE DESIGN3 .0 BOTTOM PLATE & ANNULAR PLATE DESIGN
Annular plate used ? ( yes/no ) : yes
BOTTOM PLATE(i) Minimum thickness as per API 650 Clause 5.4.1 = 5.00
Minimum thickness required (@ 3.00 mm c.a ) = 8.00Therefore, use thickness of 8.00 mm (tb) is satisfactory.
(ii) - = -(iii) Min. width of overlapping (cl. 5.1.3.5) = 25(iv) Min. width of plate (cl. 5.4.1) = 1220(v) - = 50
ANNULAR PLATE(i) Nominal thickness of 1st shell course, tsc1 = 10.00
Hydro. test stress in 1st shell course,
St =4.9Dn(H-0.3) = 48.42
whereDn = Nominal diameter, Dn ( new ) ( based on 1st shell course ) = 14.010H = Design liquid level = 7.353
= Nominal thickness of 1st shell course = 10.000
Annular plate thickness ( As per Table 5-1a ) = 6.00Minimum thickness required (@ 3.00 mm c.a. ) = 9.00Therefore , use thickness of 10.00 mm (ta) is satisfactory.
(ii) Min. shell-to-bottom fillet welds size (cl. 5.1.5.7) = 10.00(iii) Min. width projected inside of shell to edge of overlapping (cl. 5.5.2) = 600(iv) Min. radial width of annular plate (cl. 5.5.2)
La =215 ta
= 860.00
whereta = Annular plate thickness = 10.000HL = Maximum design liquid level = 7.35SG = Design specific gravity = 0.85
(v) Min. width projected outside of shell ( cl. 5.5.2) = 50
tsc1
tsc1
(HL. SG )0.5
API 650 11th Edition
mmmmmmmm
m³mm
mbargmbarg Vac°C°C
mmmm
API 650 11th Editionmmmm
Min. of t.design, t.hydo &min. thickness as per PTS.
Thicknes selected & used
Result
O.K.O.K.O.K.O.K.O.K.O.K.O.K.
#VALUE!#VALUE!
Pmax
119,894.11119,894.11131,862.31143,830.51155,798.71167,766.91179,735.11#VALUE!#VALUE!
N/m²
mmmm
mmmmmmmm
mm
N/mm²
mm
mm
mmmm
mmmm
mm
mmm
mm
8 .0 DESIGN OF SINGLE DECK FLOATING ROOF FOR A STORAGE TANK
751
64 Top pontoon plt 8Rafter L 75 x 75 x 6
Outer Rim Inner Rim
975 Post
525Btm Angle Deck Plate
Bulkhead
198 2181 3424838610
Shell I.D 39006
( All dimensions in mm unless otherwise stated. )
8 .1 TANK GEOMETRY DATAInside diameter , Di ( corroded ) (@ 39,000 mm ) = 39,006Tank height (tan/tan), H =
Material of Construction : SA 516 Gr 65NSpecific Minimum Yield Stress, Sy = 275Modulus of Elasticity = 209,000
= 7,850
Corrosion Allowance = 3Min. Specific Gravity of product = 0.7Max. Specific Gravity of product = 1
8 .2 GEOMETRY DATAOuter Rim Height, Hor = 975Inner Rim Height, Hir = 525Pontoon width, w = 2181Rim Gap = 198Outer Rim Extend above pontoon, Hext = 75
No. of Pontoons, N = 22
Outer Rim Diameter, Øor = 38610Inner Rim Diameter, Øir = 34248
Bulkhead Outer heigh, Boh = 884Bulkhead Inner heigh, Bih = 509Bulkhead Width, wb = 2157
8 .3 MEMBER SIZE & PROPERTIESOuter Rim Thk, Tor = 9Inner Rim Thk, Tir = 15Top Pontoon Thk, Ttp = 8Btm Pontoon Thk, Tbp = 8Bulkheads Thk, Tb = 8Deck Plate Thickness, Td = 8Circumferential Truss Plates = 8
Rafter 44 Nos. of L 75 x 75 x 6 @ unit weight of 6.85Posts 44 Nos. of L 75 x 75 x 6 @ unit weight of 6.85
Density of Material, r (plate)
8 .4 ROOF SUPPORT LEG ( Refer to Design of Supporting Legs)8 .4.1 PONTOON LEG
No. of Pontoon Leg, Np = 22Pontoon Leg Size 3" pipe x Sch. 80 @ unit wt 15.27Pontoon Leg Housing 4" pipe x Sch. 80 @ unit wt 22.32Pontoon Leg length = 2940Pontoon Leg Housing length = 1084
8 .4.2 DECK LEGNo. of Deck Leg, Nd (Area od deck / 30m² / leg ) = 30Deck Leg Size 3" pipe x Sch. 80 @ unit wt 15.27Deck Leg Housing 4" pipe x Sch. 80 @ unit wt 22.32Deck Leg length = 2927Deck Leg Housing length = 823
8 .5 WEIGHT CALCULATION
Top Pontoon = = 15,675.18Bottom Pontoon = 15,675.18
Inner Rim = = 6,651.28Outer Rim = = 8,355.38
Bulkheads = = 2,075.65
Deck Plate = = 57,852.21
Pontoon Legs = 987.66Pontoon Legs housing = 532.29Deck Legs = 1340.86Deck Legs housing = 551.08
TOTAL WEIGHTPontoon Components: - = 55,248.45Deck Components: - = 57,852.21Total Weight of Floating Roof, (Wroof) = 113,100.66
9 .0 PONTOON VOLUMEO. Rim Ø 38610mm
I. Rim Ø + 2 x 2/3 w 37156 mmh3 = 0.03
I. Rim Ø 34248 mmh2 = 0.53
h1 = 0.35
2
Volume 1 = 40.70
Volume 2 = 120.17
Volume 3 = 3.85
Total Pontoon Volume, Vol(pontoon) = 164.72
p/4 x( Øor² - Øir²) x Ttp x r(plate)p/4 x( Øor² - Øir²) x Tbp x r(plate)
p x Øir x Hir x Tir x rp x Øor x Hor x Tor x r
1/2 x (Boh - Bih)x wb x Tb x r x N
p/4 x Øir x Td x r
(Wpontoon)(Wdeck)
2
1
3
9 .0 SETTING DECK LEVEL9 .1 OPERATION FLOATATION LEVEL - DECK
Deck Floatation Depth=
Density of DeckDeck Thk Density of Product
x Td = 89.71
9 .2 OPERATION FLOATATION LEVEL - PONTOON
== W (Pontoon) x g
= 78.93
To find Floatation Depth of Pontoon from Inner Corner of Pontoon,
Vol. Displacement above Inner corner of PontoonPontoon Cross Area in Vol. 2
Vdisplacement - Vbackslope (Vol.1)= 153.15
Freeboard above deck,494.56Product Level
89.71153.15 Deck Level
63.44mm
The Deck is set at the difference of floation depth in Pontoon & Deck,
= 63.44 mm
9 .3 NORMAL OPERATION FLOATATION LEVEL FOR ROOF - PONTOON & DECK
Actual Product
Level 161.57 m³Deck
Level Deck
H, Floatation Height Above Deck
Total Volume Displaced by the roof=
Volume Displaced by the Backslope, V1+
Partial Volume Displaced in Pontoon below the deck level, Va+
Volume Displaced by the Deck, Vb
= 161.57
Floatation Depth, D(deck) =r (deck)
r (product)
Buoyant Force, FB Fpontoon
r x Vdisplacement x g
Product Displacement, Vdisplacement =Pontoon Weight, W(pontoon)
r (product)
D(pontoon) =
D(pontoon) = 1/4 x p x (Øor² - Øir²)
D(deck) - D(pontoon)
Total Volume Displaced by the roof, Vdisplacement (roof):
Vdisplacement (roof) =Roof Total Weight, W(roof)
r (product)
2
1
3
i) Volume Displaced by the Backslope, Volume 1 = 40.70
ii) Partial Volume Displaced in Pontoon below the deck level:
Deck level Height, hx Vol. 2 = 14.98
Bulk head outer height, Bih
iii) Volume Displaced by the Deck:
Area of Deck Plate x Floatation Height Above Deck
= 921.21
Hence, The Floatation Height Above Deck, H = 0.11114.95
9 4 FLOATATION LEVEL FOR ROOF - PONTOON & DECK FOR 10" (254MM) OF ACCUMULATED RAIN WATER
For deck to support 10" (254mm) of rain water:Volume of rain water collected at the deck, Vrain =
= 233.99
where
Area of deck = = 921,213,536.64
Rain accumulation of 10" = 254.00
W(roof) + Wt(rain)= 495.84
where
W(roof) = Total weight of roof
Wt(rain) = Weight of 10" rain water
Floatation Height above Deck, H(rain) = Vdisplacement (rain) - Vol.1 - partial of Vol.2 (ii) = 0.38
Area of roof = 375.95
10 0 CHECKING THE STRESSES AND DEFLECTION IN THE CENTRE DECK(Ref. to Roark's Formulas For Stress And Strain, 7th Edition)
10 1 CASE 1: NORMAL CASE - NO PONTOON PUNCTURED
( 11.11.1)
( 11.11.2)
Where:t = Plate thickness, Deck (mm) = Td = 8
Outer radius of the deck plate = Øir / 2 = 17124q = Unit lateral pressure (equiv. weight of deck that float on product)
= = 0.000561y = Maximum deflection
bending stressdiaphragm stress
s = Maximum stress due to flexure and diaphragm tension combinedv = Poisson's ratio = 0.3
p/4 x Øir2 x H
Vrain = Adeck x Hrain
Adeck = p/4 x Øir2
Hrain =
Total Volume Displaced by the roof with the 10" of rain water accumulation, Vdisplacement (rain):
Vdisplacement (rain) = r (product)
a =
Td x ( r(plate) - r(product) )
sb =sd =
sb + sd =
3
214
4
=
t
yK
t
yK
Et
q a
2
432
2
=
t
yK
t
yK
Et
sa
E = Modulus of Elasticity = 209,000
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as:Fixed and Held. Uniform pressure q over entire plate (Case 3 in Roark's Formulas)
5.33= 5.86
2.6= 2.86
At the Centre,2
= 2.86
= 0.976
At the edge,4
= 4.40
= 1.73
For= 56,361.13
Andy
= 56,249.31t t
y = 215.81 mm
Solving equation 11.11.2
σα² y y 2t t
= 787.3494954301 (at Deck Center)= 1377.567314837 (at Deck Edge)
At Deck Center,= 35.92= 3.52= 32.40
At Deck Edge,= 62.84= 5.41= 57.43
It is the diaphragm stress at the edge which causes the tension at the outer edge of the Deck.Hence, the radial force on the inner rim,
Rh = σ diaphgram x deck thickness = 459.44
K1 =1 - n2
K2 =1 - n2
K3 = 1 - n
K4
K3 = 1 - n2
K4
q α4
Et4
K1 + K2 y 3 q α4
Et4
= K3 + K4E. t 2
σtotal
σbending
σdiaphgram
σtotal
σbending
σdiaphgram
=
10 2 PONTOON STRESS DESIGN - CASE 110 .2.1 PONTOON PROPERTIES
Nominal diameter of Inner Rim, Øir = 342482 2160 Pontoon Inside Width = 2160
525 Inner Rim Thickness, Tir = 124 Outer Rim Thickness, Tor = 9900 Top Pontoon Thk, Ttp = 8
Btm Pontoon Thk, Tbp = 82187 3
Top Pontoon slope angle @ 1 : 64 = 0.02= 0.16
A Y AY h A.h² I = (bd³)/12(mm²) (mm) (mm³) (mm) (mm4) (mm4)
1 6300 6 37,800 1,126 7,980,578,762 75,6002 17282 1092 18,872,063 40 26,969,435 6,720,924,5253 17494 1092 19,103,800 40 27,300,602 6,971,562,4624 8100 2176.5 17,629,650 1,045 8,845,340,202 54,675
TOTAL 49,176 55,643,313 16,880,189,001 13,692,617,263Neutral axis of combined section, C1 = 1132
Moment of inertia of section , Ix-x = 30,572,806,264Section modulus available, Za = 27,019,626
10 .2.2 MATERIAL PROPERTIESMaterial Properties : SA 516 Gr. 65NSpecified minimum yield stress, Sy = 275.00Yield strength reduction factor, k ( Table M-1 ) = 1.000Allowable stress reduction factor ( App. M.3.5 ), Ks ( = k.Sy/206.7 ) = 1.00Allowable bending stress, Fb = 183.33Allowable compressive stress, Fc = 165.00
10 .2.3 PONTOON RING DESIGNThe uniform radial force acting on the Inner Rim is modelled as load point at each mm of circumference,with a very small angle between load point approximtaed to uniform distributed load in the circular ring design.
RhNumber of load point @ each mm,
= 107,593.27Mid Point 1/2 x 360/ Nlp = 0.001673
Radial load on rim, Rh = 459.44
(Reference to Roark's Formulas For Stress and Strain, 7th Edition, Table 9.2 Case 7)
At Mid-Point,Bending moment, Circ. tensile force,
Rh.Do 1 1 RhMm = - Tm =
4
At Reaction-Point,Bending moment, Circ. tensile force,
Rh.Do 1 1 RhMr = - - Tr =
4( Do= Qir, nonimial diamter of inner ring)
Backslope angle, a
a° Nlp = p x Øir Angle a° =
( Note : Rh is negative for inward force )
sin a a 2.sin a
a tan a 2 tan a
a
10 .2.4 RESULT
RING STABILITY CHECK MID-POINT LOAD-POINT
Bending Moment ( Nmm ) 19.14 -38.29Circumferential force ( N ) 7,867,429 7,867,429Bending Stress ( N/mm² ) 0.0000007 -0.000001Circumferential stress ( N/mm² ) 159.98 159.98
Allow. bending stress ( N/mm² ) 183 183.33Allow. axial stress ( N/mm² ) 165 165Unity Check 0.97 0.97Condition OK. OK.
10 .3 CASE 2: INFLUENCE OF 10" (254mm) OF RAIN ACCUMULATED ON CENTER DECK
10" Rain
For deck to support 10" (254mm) of rain water:Volume of rain water collected at the deck,
= 233.99
where
Area of deck = = 921,213,536.64
Rain accumulation of 10" = 254
= 233,988.24
Upward Bouyant Load = Deck Area x Floatation Height x Product density
= 242,429.27
Downward load due to deck steel and rain water,= 291,840.45
Nett downward force acting on deck =
= (Upward bouyant load - Downward Load)
= 53.6475 Deck Area
( 11.11.1)
( 11.11.2)
Where:t = Plate thickness, Deck (mm) = Td = 8
Outer radius of the deck plate = Øir / 2 = 17124q = Unit lateral pressure = 0.000526y = Maximum deflection
bending stressdiaphragm stress
s = Maximum stress due to flexure and diaphragm tension combinedv = Poisson's ratio = 0.3E = Modulus of Elasticity = 200,000
Vrain = Adeck x Hrain
Adeck = p/4 x Øir2
Hrain =
Weight of 10" accumulated rain water, Wrain = Vol.rain x r rain
= p/4 x (Øir)2 x H(rain) x r
= Wdeck + Wrain
a =
sb =sd =
sb + sd =
3
214
4
=
t
yK
t
yK
Et
q a
2
432
2
=
t
yK
t
yK
Et
sa
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as:Case 3 - Fixed and Held. Uniform pressure q over entire plate
5.33= 5.86
2.6= 2.86
At the Centre,2
= 2.86
= 0.976
At the edge,4
= 4.40
= 1.73
For= 55,228.70
Andy
= 55,140.73t t
y = 214.3832459 mm
Solving equation 11.11.2
σα² y y 2t t
= 777.4581305786 (at Deck Center)= 1360.154002617 (at Deck Edge)
At Deck Center,= 33.94= 3.34= 30.60
At Deck edge,= 59.37= 5.14= 54.23
It is the diaphragm stress at the edge which causes the tension at the outer edge of the Deck.Hence, the radial force on the inner rim,
Rh = σ diaphgram x deck thickness = 433.85
K1 = 1 - n2
K2 = 1 - n2
K3 = 1 - n
K4
K3 = 1 - n2
K4
q α4
Et4
K1 + K2 y 3 q α4
Et4
= K3 + K4E. t 2
σtotal
σbending
σdiaphgram
σtotal
σbending
σdiaphgram
=
vK
=
1
23
10 4 PONTOON STRESS DESIGN - CASE 210 .4.1 PONTOON PROPERTIES
Nominal diameter of Inner Rim, Øir = 34248
Section modulus available, Za2 = = 27019626.01Cross sectional area, Aa = 49,176
10 .4.2 MATERIAL PROPERTIESMaterial Properties : SA 516 Gr. 65NSpecified minimum yield stress, Sy = 275.00Yield strength reduction factor, k ( Table M-1 ) = 1.000Allowable stress reduction factor ( App. M.3.5 ), Ks ( = k.Sy/206.7 ) = 1.00Allowable bending stress, Fb = 183.33Allowable compressive stress, Fc = 165.00
10 .4.3 PONTOON RING DESIGN
The uniform radial force acting on the Inner Rim is modelled as load point at each mm of circumference,with a very small angle between load point approximtaed to uniform distributed load in the circular ring design.
RhNumber of load point @ each mm,
= 107593.271/2 x 360/ Nlp = 0.001673
Mid Point Radial load on rim, Rh = 433.85
(Reference to Roark's Formulas For Stress and Strain, 7th Edition, Table 9.2 Case 7)
At Mid-Point,Bending moment, Circ. tensile force,
Rh.Do 1 1 RhMm = - Tm =
4
At Reaction-Point,Bending moment, Circ. tensile force,
Rh.Do 1 1 RhMr = - Tr =
4
10 .4.4 RESULT
RING STABILITY CHECK MID-POINT LOAD-POINT
Bending Moment ( Nmm ) 18.08 -36.15Circumferential force ( N ) 7,429,209 7,429,209Bending Stress ( N/mm² ) 0.0000007 -0.000001Circumferential stress ( N/mm² ) 151.07 151.07
Allow. bending stress ( N/mm² ) 183 183Allow. axial stress ( N/mm² ) 165 165Unity Check 0.92 0.92Condition OK. OK.
10 .4.5 STRESSES SUMMARY
LOAD CASE 1 LOAD CASE 2Deck Center Deck Edge Deck Center Deck Edge
( N/mm² ) 35.92 62.84 33.94 59.37
( N/mm² ) 3.52 5.41 3.34 5.14
( N/mm² ) 32.40 57.43 30.60 54.23
Nlp = p x Øir a° Angle a° =
( Note : Rh is negative for inward force )
sin a a 2.sin a
a tan a 2 tan a
σtotal
σbending
σdiaphgram
11 .0 ROOF SUPPORT LEG DESIGN
22 Nos. at R4 18541.0015 Nos. at R3 13716.0010 Nos. at R2 8839.00
5 Nos. at R1 4267.00
11 .1 GEOMETRIC DATA
Support leg size = 3" Sch. 80
Pipe outside diameter = 88.9
Pipe Thickness, = 7.62
= 1,945.76Radius of gyration, r = I Do2 - Di2
= 24.894
11 .2 MATERIAL PROPERTIESMaterial of Construction for roof support leg : SA 333 Gr 6Specific Minimum Yield Stress, Sy = 241Modulus of Elasticity = 209,000
= 7,850Leg Material
11 .3 LOADING DATASupport leg length at
i) R1 : Lsp1 = 2927ii) R2 : Lsp2 = 2927
iii) R3 : Lsp3 = 2927iv) R4 : Lsp4 = 2940
Deck O.D = 34231Deck Thickness, td = 8
= 920,299,220.87
= 57,794.79
= 1.2
Effective radius for area of deck supported by leg:
= 15415.75
1/2(R3-R2) = 11277.5
1/2(R2-R1) = 6553
Area of deck supported by legs at
i) R1 = 134,905,671.69
ii) R2 = 264,648,384.82
iii) R3 = 347,030,823.13
iv) R4 = 173,714,341.24
Pipe Area, Aleg
Aleg
Density of Material, r (plate)
Deck Area, Adeck
Center deck weight, Wdeck
Design Live Load, Llive
R3eff = 1/2(Øir/2-R3)
R2eff =
R1eff=
= p(R1eff)2
= p((R2eff)2- (R1eff)2 )
= p((R3eff)2- (R2eff)2 )
= p((Ødeck)2- (R3eff)2 )
11 .4 SUPPORT LEG AT INNER DECK R1No. of legs at R1 = 5
Area of deck supported by legs at R1, A1 = 134,905,671.69
Deck area on each leg, A1' = 26,981,134.34
Deck load on one leg =A1'
= 1,694.42
= 16.62
Live load on one leg = = 32.38Total load on one leg = Deck load + Live load = 49.00
Stress on support leg at inner deck R1, P1 = = 25.18
11 .4.1 ALLOWABLE STRESSAs per AISC code,Slenderness ratio,l = K.Lsp1 / Rx-x = 118whereK = 1Column slenderness ratio dividing elastic and inelastic buckling,
Cc = = 130.84 Sy
Sc.all = (i) = 75.08
Sc.all = (ii) = 77.80
Smaller of (i) or (ii)Sc.all = = 74.20
In this case, the allowable stress Sc.all is = 75.08
Since P1 < Sc.all, the support leg at inner deck R1 is satisfactory.
11 .5 SUPPORT LEG AT INNER DECK R2No. of legs at R2 = 10
Area of deck supported by legs at R2, A2 = 264,648,384.82
Deck area on each leg, A2' = 26,464,838.48
Deck load on one leg =A2'
= 1,661.99
= 16.30
Live load on one leg = = 31.76Total load on one leg = Deck load + Live load = 48.06
Stresses on support leg at inner deck R2, P2 = = 24.70
11 .5.1 ALLOWABLE STRESSAs per AISC code,Slenderness ratio,l = K.Lsp2 / Rx-x = 118whereK = 1Column slenderness ratio dividing elastic and inelastic buckling,
Cc = = 130.84 Sy
Wdeck xAdeck
Llive x A1'
Total Load / Aleg
2p²E
When l £ Cc, [ 1 - l² / 2Cc² ].Sy
5/3 + 3l /8Cc - l³/8Cc³When Cc £ l £ 120,
12p²E
23 l²When 120 £ l £ 200,
1.6 - l/200
Wdeck xAdeck
Llive x A2'
2p²E
Sc.all = (i) = 75.08
Sc.all = (ii) = 77.80
Smaller of (i) or (ii)Sc.all = = 74.20
In this case, the allowable stress Sc.all is = 75.08
Since P2 < Sc.all, the support leg at inner deck R2 is satisfactory.
11 .6 SUPPORT LEG AT INNER DECK R3No. of legs at R3 = 15
Area of deck supported by legs at R3, A3 = 347,030,823.13
Deck area on each leg, A3' = 23,135,388.21
Deck load on one leg =A3'
= 1,452.90
= 14.25
Live load on one leg = = 27.76Total load on one leg = Deck load + Live load = 42.02
Stresses on support leg at inner deck R3, P3 = = 21.59
11 .6.1 ALLOWABLE STRESSAs per AISC code,Slenderness ratio,l = K.Lsp3 / Rx-x = 118whereK = 1Column slenderness ratio dividing elastic and inelastic buckling,
Cc = = 130.84 Sy
Sc.all = (i) = 75.08
Sc.all = (ii) = 77.80
Smaller of (i) or (ii)Sc.all = = 74.20
In this case, the allowable stress Sc.all is = 75.08
Since P3 < Sc.all, the support leg at inner deck R3 is satisfactory.
When l £ Cc, [ 1 - l² / 2Cc² ].Sy
5/3 + 3l /8Cc - l³/8Cc³When Cc £ l £ 120,
12p²E
23 l²When 120 £ l £ 200,
1.6 - l/200
Wdeck xAdeck
Llive x A3'
Total Load / Aleg
2p²E
When l £ Cc, [ 1 - l² / 2Cc² ].Sy
5/3 + 3l /8Cc - l³/8Cc³When Cc £ l £ 120,
12p²E
23 l²When 120 £ l £ 200,
1.6 - l/200
11 .7 SUPPORT LEG AT PONTOONNo. of legs at R4 = 27
Area of deck supported by legs at R4, A4 = 173,714,341.24
Deck area on each leg, A4' = 6,433,864.49
Deck load on one leg =A4'
= 404.05
= 3.96
= 55,248.45
= 5,022.59= 49.27
Live load on one leg = = 7.72Total load on one leg = Deck load + Live load + Pontoon weight = 60.96
Stresses on support leg at Pontoon, P4 = = 31.33
11 .7.1 ALLOWABLE STRESSAs per AISC code,Slenderness ratio,l = K.Lsp4 / Rx-x = 118whereK = 1Column slenderness ratio dividing elastic and inelastic buckling,
Cc = = 130.84 Sy
Sc.all = (i) = 74.62
Sc.all = (ii) = 77.12
Smaller of (i) or (ii)Sc.all = = 73.93
In this case, the allowable stress Sc.all is = 74.62
Since P3 < Sc.all, the support leg at inner deck R3 is satisfactory.
11 .8 STRESSES SUMMARY
Leg at radius No. of leg RESULT
4267.00 5.00 25.18 75.08 OK8839.00 10.00 24.70 75.08 OK13716.00 15.00 21.59 75.08 OK18541.00 22.00 31.33 74.62 OK
Wdeck xAdeck
Pontoon weight, Wpontoon
Pontoon weight on one leg, Wpontoon'
Llive x A4'
Total Load / Aleg
2p²E
When l £ Cc, [ 1 - l² / 2Cc² ].Sy
5/3 + 3l /8Cc - l³/8Cc³When Cc £ l £ 120,
12p²E
23 l²When 120 £ l £ 200,
1.6 - l/200
Actual stress, (N/mm2)
Allowable stress, (N/mm2)
15
8
mm
N/mm²N/mm²kg/m³
mm
mmmmmmmmmm
mmmm
mmmmmm
mmmmmmmmmmmmmm
kg/mkg/m
kg/mkg/mmmmm
kg/mkg/mmmmm
kgkg
kgkg
kg
kg
kgkgkgkg
kgkgkg
m³
m³
m³
m³
mm
m³
mm
m³
m³
H
mmm
m³
mm
m³
mmm
mm2
N/mm2
N/mm²
N/mm
N/mm2
N/mm2
N/mm2
N/mm2
N/mm2
N/mm2
mmmmmmmm
radrad
mm
mm³
N/mm²
N/mm²N/mm²
°N
mm4
for inward force )
m³
mm³
mm
kg
kg
kg
N/mm²
kg/m2
N/mm2
N/mm
N/mm2
N/mm2
N/mm2
N/mm2
N/mm3
N/mm4
mm
mm²
N/mm²
N/mm²N/mm²
°N/ load pt
mm3
mm
mm
N/mm²N/mm²kg/m³
mmmmmmmm
mmmm
kg
mm2
mm2
KN/m2
mm2
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mm2
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kg
KN
KNKN
N/mm²
N/mm²
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N/mm²
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KN
KNKN
mm2
mm2
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N/mm²
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KNKN
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KNKN
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mm2
N/mm2
BLEEDER VENT CALCULATION12 .0 DESIGN OF AIR VENTING SYSTEM12 .1 GEOMETRIC DATA
Design Code : API STD 2000 Inside diameter, Di = 39000Tank height, H = 20700Nominal Capacity 24000Design pressure, Pi = 2.50Flash point (FP)/Normal boiling point (NBP) (@ FP ) = 67Filling rate ( Pumping in/Flow rate to tank ), Vi = 427Emptying rate ( Pumping out/Flow rate from tank ), Vo = 1,100
OPERATING VENTING12 .2 NORMAL VACUUM VENTING12 .2.1 Maximum liquid movement out of a tank
Flow rate of free air, Vv1 ( = Vo/15.9 x 15.89 ) = 1097.23
12 .2.2 Thermal inbreathingTank capacity, V = 155,535From Table 2, column 2 (Thermal Venting Capacity Req't ),Flow rate of free air,Vv2 ( @ 0 ft³/hr ) = 0
Total vacuum flow required, Vv ( = Vv1 + Vv2 ) = 1,097
12 .3 NORMAL PRESSURE VENTING12 .3.1 Maximum liquid movement into a tank
Rate of free air per 0.159m³/hr of product import rate, m = 0.17Flow rate of free air, Vp1 ( = Vi/0.159 x m ) = 457
12 .3.2 Thermal outbreathingFrom Table 2, column 3 (Thermal Venting Capacity Req't),Flow rate of free air,Vp2 ( @ 0 ft³/hr ) = 0
Total pressure flow required, Vp ( = Vp1 + Vp2 ) = 457
OPEN VENT SIZING ( BLEEDER VENT SIZING )12 .4 OPEN VENT SIZING CALCULATION
Maximum flow, Q ( @ Vacuum flow at ( @ 2.50 mbarg. ) = 1,097
Q = K. A. 2. g. H
whereK = Discharge coefficient 0.62A = cross sectional area of ventg = acceleration due to gravityH = Head as measure pressure differential
H = = 21 g
Minimum require cross sectional area of vent,
Q Q g = 0.0241K. 2. g. H K = 24,124
whereQ = Max. Air flow required = 0.3048
g = Specific weight of Air = 11.812r = Air density = 1.204
Differential pressure = 250
12 .5 BLEEDER VENT SELECTEDSelected bleeder vent size : 8" Sch StdNumber of vent, N = 1Outside diameter of the vent, do 219Inside Dia. of one vent , di ( @ vent pipe thickness = 8.18 mm ) = 202.64
= 32,251
Dp
Av_req = 2. g. Dp
= r g
Dp =
Total cross sectional area of vents, Av_actual
=
> Ar_gnv, therefore the nos. & size of vents is satisfactory.Since Av_actual
mmmmm³mbarg°Cm³/hrm³/hr
m³/hr
barrels
m³/hr
m³/hr
m³/hrm³/hr
m³/hr
m³/hr
m³/hr
m
m²mm²
mm³/s
kg/m³N/m²
mmmm²
kg/m2s2
13 .0 ROOF DRAIN DESIGN
Rigid Pipe
1275 Flexible pipe
225Rigid Pipe
13 .1 GEOMETRIC DATATank Nominal Diameter =Tank Height, =Roof lowest height, H =Drain outlet nozzle elevation, z =
Roof Deck Area =
Design Rain Fall =
Design drainage required, Qreq. =
No. of Roof Drain, N =Roof drain pipe size (rigid & fitting) =Dain Pipe Outside Diameter, Do =Drain pipe thickness =
Drain Pipe length :L1 = Rigid 20 m x 2 nos. =L2 = Flexible 23.14 m x 1 nos. =
13 .2 Number of Fitting & Accessories per drain pipe
- =
- =
- Valve =- Rigid pipe =- Flexible pipe =
13 .3 TOTAL HEAD
H = h + 2g
45º elbow N45º
90º elbow N90º
Nv
V2
13 .4 TOTAL HEAD LOSS OF ROOF DRAIN PIPE
K L'2g D
WhereH = Total head between the lowest position of deck and the =
roof drain nozzleG = Gravity accelerationK = Friction Coefficient
- For rigid pipe : =
- For flexible pipe : =L' = Total equivalent length of drain pipeD = Inside Diameter of drain pipe =
13 .5 EQUIVALENT PIPE LENGTH OF VALVE AND FITTING Accordance to NFPA 15 Table 8.5.2.1,
Equivalent length for 4" =
=
=
=
=
13 .6 TOTAL HEAD LOSS OF ROOF DRAIN PIPE
2g D D
+ 12g D D
13 .7 FLOW VELOCITY2 g H
V = + 1
= D D
13 .8 DRAINAGE FLOW RATE PER DRAIN PIPEQ = AREA x Velocity
= =
13 .9 MINIMUM ROOF DRAIN REQUIRED
Nreq =Drainage flow rate required
=Actual flow rate per drain
MINIMUM REQUIRED =
V2
K1
K2
45º elbow, L45º
90º elbow, L90º
Valve, Lv
Total equivalent pipe length for RIGID PIPE:
L1' = L1 + N45º x L45º + N90º x L90º + Nv x Lv
Total equivalent pipe length for Flexible PIPE:
L2' = L2
V2 K1 L1' K2 L2'
V2 K1 L1' K2 L2'
K1 L1' K2 L2'
p/4 x D2 x V x 3600 (s/hr)
h = x
h = x +
H =
H = +
+
39,000 mm20,100 mm
1500 mm225 mm
920.30
50 mm/hr
46.01
24" Sch 80
101.6 mm8.56 mm
40 m23.14 m
2
1
121
m2
m3/ hr
1.275 m
0.0168
0.03
0.08448 m
3.1
1.2
0.6
48 m
23.14 m
1.15 m/s
23.30
1.97
2
m3 / hr
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14 WEIGHT ANALYSIS
ITEM NO : 1
1 GENERALDesign Type of roof support : Type of roofcode : API 650 11th Edition NA : Cone-roofInside Tank heightdiameter : 14,000 mm : 7,353 mmSteel density Roof plates lapping Annular/Bottom plates lappingShell / Btm : 7,850 kg/m³ factor : 7.35 factor : 1Roof : 8,027 kg/m³
2 SHELL COURSES
ONE - FOOT METHOD (OUTER TANK) YCourse No. Material Thickness Width Weight
(mm) (mm) (kg)1 A 516 GR. 65N 10.00 1,220 4,2152 A 516 GR. 65N 10.00 1,220 4,2153 A 516 GR. 65N 10.00 1,220 4,2154 A 516 GR. 65N 10.00 1,220 4,2155 A 516 GR. 65N 10.00 1,220 4,2156 A 516 GR. 65N 10.00 1,220 4,2157 A 516 GR. 65N 10.00 1,220 4,2158 - 0.00 2,020 -9 - 0.00 -3,207 -10 - - - -
Total weight of shell plates = 29,506 kg
3 BOTTOM PLATES YMaterial Thickness Outside Dia. Weight
(mm) (mm) (kg)A 516 GR. 65N 8.00 14,130 9,848 = 9,848 kg
4 TOP CURB ANGLE YMaterial Size Qty Length Unit Weight Weight
(mm) (kg/m) (kg)A 516 GR. 65N 76 x 76 x 6.4 1 44,218 10.33 457 = 457 kg
5 TOP WIND GIRDERS YMaterial Size Qty Length Unit Weight Weight
(mm) (kg/m) (kg)A 516 GR. 65N T 825 x 250 x 8 x 10 1 46,574 83.74 3,900 = 3,900 kg
6 INTERMEDIATE WIND GIRDERS YMaterial Size Qty Length Unit Weight Weight
(mm) (kg/m) (kg)A 516 GR. 65N T 405 x 150 1 45,867 49.99 2,293 = 2,293 kg
7 NOZZLES YTotal weight of nozzles 1,500 = 1,500 kg
8 MISCELLANEOUS YAssuming 5.00 % of total weight 2,375 = 2,375 kg
9 STAIRWAY & PERIMETER PLATFORM YPlatform Weight 165.00 KN 16,820 = 16,820 kg
10 OPERATING LIQUID WEIGHTOperating liquid height (@ = 7,353 mm & sg @= 0.85 ) = 962,120 kg
11 HYDROSTATIC WATER WEIGHTHydrostatic water height (@ 7,353 mm ) = 1,131,906 kg
ERECTION WEIGHT (Exclude roof) = 66,699 kgOPERATING WEIGHT = 1,028,819 kgFIELD HYDROSTATIC TEST WEIGHT = 1,198,605 kg
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Tank Capacity
C=
Input Data:D= 14 m.H= 6.5 m.
C= 1,000.00 cu.m.
0.785*D2H
RAPTER DATA
Rafter Material = ASTM A-36Allowable Design Strees (Sd) = 160 MpaRafter Selection
Ring Name Type of RafterZ R Weight Area
m kg/m1 C 75x40x5 20080 0.0292 6.922 C 75x40x5 20080 0.0292 6.923 C 75x40x5 20080 0.0292 6.92
RAFTER DESIGN
Nominal Roof Thickness = 6 mm
Roof Plate Weight = 47.2
Added Dead Load = 20
= 100
Specific Snow Load (S) = 0
= 0 Kpa
= 0
Insulation+ Plate Weight+Added Dead Load
67.2
ROOF LOAD PER API-650 APPENDIX RLOAD COMBINATION (L1)
L1 =
167.2
LOAD COMBINATION (L2)L2 = DL+Pe+0.4*MAX (S,Lr)
107.2
BALANCE ROOF DESIGN LOAD (T)
T =use L1
T= 167.21.64 Kpa
MAXIMUM RAFTER SPACING PER API 650 5.10.4.4Maximum Rafter Spacing (b)
b = (t-c)* sqrt (1.5*Fy/T)b = 2391 mm
SPACING OF RAFTERSFor outer Shell Ring
Ring Radius = 7 m
b = 2391 mm
mm3 m2
kg/m2
kg/m2
Minimum Roof Live Load (Lr) kg/m2
kg/m2
Specified external pressure (Pe)
kg/m2
Dead Load (DL) =
kg/m2
DL+MAX(S,Lr)+0.4*Pe
kg/m2
kg/m2
MAX(L1,L2)
kg/m2